The purpose of the study is to examine whether or not the quadruple regimen of 141W94 1200 mg bid, abacavir 300 mg bid, and Combivir (TM) bid is superior in efficacy to the triple regimen of Nelfinavir 750 mg tid and Combivir (TM) bid in antiretroviral-naive, HIV-infected subjects with baseline HIV RNA > or = 5000 copies/mL and baseline CD4 > or = 50 cells/mme, in the presence of comparable safety and tolerability profiles for the treatment arms.